Accessing /dev/video0 locks kernel tight

When I try to access a v4l2 device, the screen turns black and my kernel locks.  I have to hard reset to get the system back.  The box stops responding to pings, mouse pointer locks tight, screen turns back with flashing cursor in top left...
This code will lock up my machine:
ffmpeg -s 320x240 -f video4linux2 -i /dev/video0 output.ogv
Confusingly, I can launch vlc and media->capture device, select video4linux2, and enter /dev/video0 in the video device name field.  That works.  It even streams video.  It's working right now.
Here is my kernel.
2.6.33-ARCH #1 SMP PREEMPT Sun Apr 4 10:27:30 CEST 2010
I would appreciate some ideas.  How come vlc works but ffmpeg doesn't?  I've also tried ffmpeg2theora.  It behaves the same as ffmpeg.
Here is the output from "ffmpeg -version":
FFmpeg version SVN-r22837, Copyright (c) 2000-2010 the FFmpeg developers
built on Apr 11 2010 19:46:29 with gcc 4.4.3 20100316 (prerelease)
configuration: --prefix=/usr --enable-gpl --enable-libmp3lame --enable-libvorbis --enable-libfaac --enable-libfaad --enable-libxvid --enable-libx264 --enable-libtheora --enable-postproc --enable-shared --enable-pthreads --enable-x11grab --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-version3 --enable-nonfree --enable-runtime-cpudetect
libavutil 50.14. 0 / 50.14. 0
libavcodec 52.66. 0 / 52.66. 0
libavformat 52.61. 0 / 52.61. 0
libavdevice 52. 2. 0 / 52. 2. 0
libswscale 0.10. 0 / 0.10. 0
libpostproc 51. 2. 0 / 51. 2. 0
FFmpeg SVN-r22837
libavutil 50.14. 0 / 50.14. 0
libavcodec 52.66. 0 / 52.66. 0
libavformat 52.61. 0 / 52.61. 0
libavdevice 52. 2. 0 / 52. 2. 0
libswscale 0.10. 0 / 0.10. 0
libpostproc 51. 2. 0 / 51. 2. 0
Last edited by TomB17 (2010-04-17 14:49:00)

So far, no crashes after the downgrade today (3.3.4-1 -> 3.3.3-1).
Compiling today does not even result in any intense swapping activity.
# sysctl vm.swappiness
vm.swappiness = 60
Here is the peaking moment of swap utilization while compiling. I don't recall exactly what these numbers where yesterday.
# free -m
total used free shared buffers cached
Mem: 499 493 5 0 0 354
-/+ buffers/cache: 137 361
Swap: 486 83 402
Thanks for the guidance.
[EDIT]: Things are very clearly different today. The kernel downgrade did it for me. I'll mark this topic [SOLVED]. Thanks a bunch.
[EDIT2]: The commenters at https://bugs.archlinux.org/task/29694 are offering details that may help someone here.
Last edited by zero2cx (2012-05-01 20:40:54)

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    Sen

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